U.S. patent number 8,185,290 [Application Number 12/073,669] was granted by the patent office on 2012-05-22 for data acquisition system indexed by cycle segmentation.
This patent grant is currently assigned to Caterpillar Inc.. Invention is credited to Vijayakumar Janardhan, Kevin D. King, Brian Mintah, Robert J. Price, Shoji Tozawa.
United States Patent |
8,185,290 |
Mintah , et al. |
May 22, 2012 |
Data acquisition system indexed by cycle segmentation
Abstract
A data acquisition system for an excavation machine having a
power source configured to drive a tool through a work cycle is
disclosed. The data acquisition system may have a first sensor
associated with the power source to generate a first signal
indicative of a performance of the power source, and a second
sensor associated with the tool to generate a second signal
indicative of a performance of the tool. The data acquisition
system may also have a controller in communication with the first
and second sensors. The controller may be configured to record the
first and second signals, and partition the work cycle into a
plurality of segments. The controller may be further configured to
link the performance of the power source and the performance of the
tool together with one of the plurality of segments during which
the associated first and second signals were recorded.
Inventors: |
Mintah; Brian (Washington,
IL), Price; Robert J. (Dunlap, IL), King; Kevin D.
(Peoria, IL), Janardhan; Vijayakumar (Washington, IL),
Tozawa; Shoji (Kobe, JP) |
Assignee: |
Caterpillar Inc. (Peoria,
IL)
|
Family
ID: |
41054497 |
Appl.
No.: |
12/073,669 |
Filed: |
March 7, 2008 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20090228176 A1 |
Sep 10, 2009 |
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Current U.S.
Class: |
701/99; 172/3;
701/50; 37/379 |
Current CPC
Class: |
E02F
9/24 (20130101); E02F 3/435 (20130101); E02F
9/267 (20130101); E02F 9/264 (20130101) |
Current International
Class: |
G06F
19/00 (20060101) |
Field of
Search: |
;701/99-115 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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2004-114081 |
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Apr 2004 |
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JP |
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2004-114081 |
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Apr 2004 |
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JP |
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Primary Examiner: Keith; Jack W
Assistant Examiner: Tissot; Adam
Attorney, Agent or Firm: Finnegan, Henderson, Farabow,
Garrett & Dunner LLP
Claims
What is claimed is:
1. A data acquisition system for an excavation machine having a
power source configured to drive a tool through repeated excavation
work cycles during operation of the machine, the data acquisition
system comprising: a plurality of sensors including: a first sensor
associated with the power source to generate a first signal
indicative of a performance of the power source; a second sensor
associated with the tool to generate a second signal indicative of
a performance of the tool; and a controller in communication with
the plurality of sensors, the controller being configured to:
record the first and second signals; partition an excavation work
cycle of the repeated excavation work cycles into a plurality of
segments based on signals from at least one of the plurality of
sensors, each segment of the plurality of segments being indicative
of a separate task performed by the machine during the excavation
work cycle; identify a set of qualified samples for at least one
segment of the plurality of segments of the excavation work cycle
from the recorded second signals, the qualified samples being a set
of the recorded second signals in the at least one segment having a
swing velocity of the tool within a user-defined range; and compute
the performance of the power source and the performance of the tool
separately for the at least one segment of the excavation work
cycle, the performance of the tool being computed using the
identified qualified samples.
2. The data acquisition system of claim 1, wherein: the performance
of the power source is a fuel consumption of the power source.
3. The data acquisition system of claim 1, wherein the performance
of the tool is a payload moved by the tool.
4. The data acquisition system of claim 3, wherein the controller
is further configured to calculate a payload moved by the tool per
completed excavation work cycle.
5. The data acquisition system of claim 1, wherein the controller
is further configured to calculate an amount of fuel consumed
during each segment of the plurality of segments of the excavation
work cycle.
6. The data acquisition system of claim 1, further including a
timer, wherein the controller is in communication with the timer
and further configured to record an elapsed period of time taken to
complete each segment of the plurality of segments.
7. The data acquisition system of claim 1, wherein the controller
is configured to link the performances of the power source and the
tool together with the one of the plurality of segments after the
tool has completed the excavation work cycle.
8. The data acquisition system of claim 1, wherein the controller
is further configured to: compare the performances of the power
source and the tool for each of the plurality of segments to a
threshold performance level; and alert an operator of the
excavation machine when the performances for at least one of the
plurality of segments are below the threshold performance
level.
9. A method of acquiring data in a machine having a power source
that is configured to drive a tool through repeated excavation work
cycles during operation of the machine, comprising: generating a
power output; directing the power output to the tool to perforin an
excavation work cycle of the repeated excavation work cycles;
sensing a plurality of parameters of the machine, including:
sensing a first parameter indicative of a performance of the power
source; sensing a second parameter associated with a performance of
the tool during the excavation work cycle; recording the first and
second parameters; partitioning the excavation work cycle into a
plurality of segments based on at least one of the sensed plurality
of parameters, each segment of the plurality of segments being
indicative of a separate task performed by the machine during the
excavation work cycle; identifying a set of qualified samples for
at least one segment of the plurality of segments of the excavation
work cycle from the recorded second parameters, the qualified
samples being a set of the recorded second parameters in the at
least one segment having a swing velocity of the tool within a
user-defined range; and computing the performance of the power
source and the performance of the tool separately for the at least
one segment of the excavation work cycle, the performance of the
tool being computed using the identified qualified samples.
10. The method of claim 9, wherein: the first parameter is related
to a fuel consumption; and the second parameter is related to an
amount of material moved during the excavation work cycle.
11. The method of claim 10, further including calculating an amount
of material moved per amount of fuel consumed to move the
material.
12. The method of claim 10, further including calculating an amount
of fuel consumed during each of the plurality of segments.
13. The method of claim 10, further including calculating an amount
of idle time during the excavation work cycle.
14. The method of claim 9, further including recording an elapsed
period of time required for completion of each segment of the
plurality of segments, and associating the elapsed period of time
to complete each segment with the performance of the power source
and the performance of the tool of that segment.
15. The method of claim 9, further including: comparing the
performance of the power source and the performance of the tool for
each segment of the plurality of segments to threshold performance
levels; and alerting an operator when the compared performance
parameters for at least one segment of the plurality of segments
are below the threshold performance level.
16. An excavation machine, comprising: a combustion engine
configured to generate a power output; a plurality of sensors
configured to measure operating parameters of the machine,
including: a first sensor associated with the combustion engine to
generate a first signal indicative of a fuel consumption of the
combustion engine; a second sensor associated with an excavation
tool of the machine to generate a second signal indicative of a
payload moved by the tool; a tool driven by the power output to
move through repeated excavation work cycles during operation of
the machine; and a controller in communication with the first and
second sensors, the controller being configured to: record the
first and second signals; partition the excavation work cycle into
a dig segment, a loaded swing segment, a dump segment, and an empty
swing segment based on readings from at least one sensor of the
plurality of sensors; identify a set of qualified samples for at
least the loaded swing segment from the recorded second signals,
the qualified samples being a set of second signals measured when a
swing velocity of the tool is within a user-defined range; and
determine the fuel consumption of the combustion engine and the
payload moved by the tool for at least the loaded swing segment,
the payload moved by the tool for at least the loaded swing segment
being computed using the identified qualified samples.
17. The excavation machine of claim 16, wherein the controller is
further configured to calculate at least one of: a payload moved by
the tool per amount of fuel consumed by the power source; and a
payload moved by the tool per completed work cycle.
18. The excavation machine of claim 16, further including a timer,
wherein the controller is in communication with the timer and
further configured to record an elapsed period of time required for
completion of each of the dig, loaded swing, dump, and empty swing
segments.
19. The data acquisition system of claim 1, wherein the qualified
samples include a set of second signals that start and end at about
the same swing velocity.
20. The method of claim 9, wherein the qualified samples include a
set of second parameters that start and end at about the same swing
velocity.
Description
TECHNICAL FIELD
The present disclosure relates generally to a data acquisition
system, and more particularly, to a data acquisition system that is
indexed by work cycle segmentation.
BACKGROUND
Excavation machines are often equipped with sensors for measuring
various operating conditions of the machines. These operating
conditions can include, for example, engine RPM, oil pressure,
water temperature, boost pressure, oil contamination levels,
electric motor current, hydraulic pressures, system voltage, fuel
consumption, payload, ground speed, transmission ratio, cycle time,
global position, and the like. A data acquisition system can be
provided on each machine for receiving the operating conditions,
processing data, and generating an operating condition database for
subsequent evaluation of machine performance.
One such data acquisition system is disclosed in U.S. Patent
Publication No. 2005/0267713 (the '713 publication) by Horkavi et
al. published Dec. 1, 2005. Specifically, the '713 publication
discloses a data acquisition system for a work machine that has at
least one sensor disposed on the work machine. The at least one
sensor is configured to produce a signal indicative of an operating
parameter of the work machine. The data acquisition system also has
an identification module disposed on the work machine and
configured to receive an input corresponding to a machine operator.
The data acquisition system further has a controller disposed on
the work machine and in communication with the at least one sensor
and the identification module. The controller is configured to
record and link the signal and the input. The data acquisition
system additional has a communication module disposed on the work
machine and in communication with the controller. The communication
module is configured to transfer the recorded and linked signal and
input from the controller to an off-board system.
In one example, the sensor of the '713 publication is associated
with a power source and a work implement to generate signals
indicative of fuel consumption and payload. The fuel consumption
and payload information is directed to the controller, which
indexes the information according to the operator controlling the
work machine at the time the information is recorded. The
controller also generates and maintains a time of day and date
associated with the recorded information. In this manner,
post-processing of the recorded and indexed information may be
performed to determine how performance of the work machine varied
during a particular work shift according to the operator that was
controlling the machine.
Although the data acquisition system of the '713 publication may
record and post-process some machine performance parameters, the
usefulness of the information generated by the system may be
limited. That is, the data is only indexed according to operator
identification and/or time, and other important indexing parameters
such as cycle segmentation may be neglected.
The disclosed system is directed to overcoming one or more of the
problems set forth above.
SUMMARY
One aspect of the present disclosure is directed to a data
acquisition system for an excavation machine having a power source
configured to drive a tool through a work cycle. The data
acquisition system may include a first sensor associated with the
power source to generate a first signal indicative of a performance
of the power source, and a second sensor associated with the tool
to generate a second signal indicative of a performance of the
tool. The data acquisition system may also include a controller in
communication with the first and second sensors. The controller may
be configured to record the first and second signals, and partition
the work cycle into a plurality of segments. The controller may be
further configured to link the performance of the power source and
the performance of the tool together with one of the plurality of
segments during which the associated first and second signals were
recorded.
Another aspect of the present disclosure is directed to a method of
acquiring data. The method may include generating a power output,
sensing a first performance parameter associated with generation of
the power output, directing the power output to complete an
excavation work cycle, and sensing a second performance parameter
associated with completion of the excavation work cycle. The method
may also include recording the first and second performance
parameters, and partitioning the excavation work cycle into a
plurality of segments. The method may further include linking the
first and second performance parameters together with one of the
plurality of segments during which the associated first and second
performance parameters were recorded.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a diagrammatic illustration of an exemplary disclosed
machine;
FIG. 2 is a schematic illustration of an exemplary disclosed data
acquisition system that may be used with the machine of FIG. 1;
FIG. 3 is an exemplary disclosed control map that may be used by
the data acquisition system of FIG. 2;
FIG. 4 is an exemplary portion of the control map illustrated in
FIG. 3; and
FIG. 5 is a control diagram illustrating an exemplary operation
performed by the data acquisition system of FIG. 2.
DETAILED DESCRIPTION
FIG. 1 illustrates an exemplary machine 10 having multiple systems
and components that cooperate to excavate and load earthen material
onto a nearby haul vehicle 12. In one example, machine 10 may
embody a hydraulic excavator. It is contemplated, however, that
machine 10 may embody another type of excavation machine such as a
backhoe, a front shovel, a dragline excavator, or another similar
machine. Machine 10 may include, among other things, a power source
13 configured to produce a power output, an implement system 14
driven by the power output to move a work tool 16 between a dig
location 18 within a trench and a dump location 20 over haul
vehicle 12, and an operator station 22 for manual control of power
source 13 and/or implement system 14.
Power source 13 may embody a combustion engine such as, for
example, a diesel engine, a gasoline engine, a gaseous fuel-powered
engine, or any other engine apparent to one skilled in the art.
Alternatively, power source 13 may embody a non-combustion source
of power such as a battery, a fuel cell, or a motor, if desired.
The output of power source 13 may be directed to pressurize
hydraulic fluid used to move implement system 14.
Implement system 14 may include a linkage structure acted on by
fluid actuators to move work tool 16. Specifically, implement
system 14 may include a boom member 24 vertically pivotal relative
to a work surface 26 by a pair of adjacent, double-acting,
hydraulic cylinders 28 (only one shown in FIG. 1). Implement system
14 may also include a stick member 30 vertically pivotal about a
horizontal axis 32 by a single, double-acting, hydraulic cylinder
36. Implement system 14 may further include a single,
double-acting, hydraulic cylinder 38 operatively connected to work
tool 16 to pivot work tool 16 vertically about a horizontal pivot
axis 40. Boom member 24 may be pivotally connected to a frame 42 of
machine 10. Frame 42 may be pivotally connected to an undercarriage
member 44, and swung about a vertical axis 46 by a swing motor 49.
Stick member 30 may pivotally connect boom member 24 to work tool
16 by way of pivot axes 32 and 40. It is contemplated that a
greater or lesser number of fluid actuators may be included within
implement system 14 and connected in a manner other than described
above, if desired.
Numerous different work tools 16 may be attachable to a single
machine 10 and controllable via operator station 22. Work tool 16
may include any device used to perform a particular task such as,
for example, a bucket, a fork arrangement, a blade, a shovel, or
any other task-performing device known in the art. Although
connected in the embodiment of FIG. 1 to pivot and swing relative
to machine 10, work tool 16 may alternatively or additionally
rotate, slide, or move in any other manner known in the art.
Operator station 22 may be configured to receive input from a
machine operator indicative of a desired work tool movement.
Specifically, operator station 22 may include one or more operator
input devices 48 embodied as single or multi-axis joysticks located
proximal an operator seat (not shown). Operator input devices 48
may be proportional-type controllers configured to position and/or
orient work tool 16 by producing a work tool position signal that
is indicative of a desired work tool speed and/or force in a
particular direction. The position signal may be used to actuate
any one or more of hydraulic cylinders 28, 36, 38 and/or swing
motor 49. It is contemplated that different operator input devices
may alternatively or additionally be included within operator
station 22 such as, for example, wheels, knobs, push-pull devices,
switches, pedals, and other operator input devices known in the
art. It is also contemplated that operator station 22 may include
an interface device (not shown) for use in receiving operator
instructions and/or displaying machine performance information, if
desired.
As illustrated in FIG. 2, machine 10 may include a data acquisition
system 50 configured to monitor, record, and/or control movements
of work tool 16 (referring to FIG. 1). In particular, hydraulic
data acquisition system 50 may include a controller 60 in
communication with a plurality of sensors. In one embodiment,
controller 60 may be in communication with a first boom sensor 62A,
a second boom sensor 62B, a swing sensor 64, a bucket sensor 65, a
stick sensor 67, and a power source sensor 69. Based on input
received from these sensors, controller 60 may be configured to
partition a typical work cycle performed by machine 10 into a
plurality of segments, for example, into a dig segment, a
swing-to-truck segment (i.e., a loaded swing segment), a dump
segment, and a swing-to-trench segment (i.e., an empty swing
segment); to monitor a payload during a selected one of these
segments; to monitor and analyze the performance of power source
13; and/or to display the performance machine 10 as will be
described in more detail below.
Controller 60 may embody a single microprocessor or multiple
microprocessors that include a means for performing an operation of
data acquisition system 50. Numerous commercially available
microprocessors can be configured to perform the functions of
controller 60. It should be appreciated that controller 60 could
readily embody in a general machine microprocessor capable of
controlling numerous machine functions. Controller 60 may include a
memory, a secondary storage device, a processor, and any other
components for running an application. Various other circuits may
be associated with controller 60 such as power supply circuitry,
signal conditioning circuitry, solenoid driver circuitry, and other
types of circuitry.
One or more maps 66 relating signals from sensors 62A, 62B, 64, 65,
and 67 to the different segments of the typical excavation work
cycle may be stored within the memory of controller 60. Each of
these maps may include a collection of data in the form of tables,
graphs, and/or equations. In one example, threshold speeds
associated with the start and/or end of one or more of the segments
may be stored within the maps. In another example, threshold forces
associated with the start and/or end of one or more of the segments
may be stored within the maps. In yet another example, a speed
and/or a force of work tool 16 may be recorded into the maps
throughout each excavation work cycle and subsequently analyzed by
controller 60 during partitioning of the excavation work cycle.
Controller 60 may be configured to allow the operator of machine 10
to directly modify these maps and/or to select specific maps from
available relationship maps stored in the memory of controller 60
to affect cycle partitioning and/or payload monitoring. It is
contemplated that the maps may additionally or alternatively be
automatically selectable based on modes of machine operation, if
desired.
First boom sensor 62A may be associated with the vertical pivoting
motion of work tool 16 imparted by hydraulic cylinders 28 (i.e.,
associated with the lifting and lowering motions of boom member 24
relative to frame 42). Specifically, first boom sensor 62A may be
an angular position or speed sensor associated with a pivot joint
between boom member 24 and frame 42, a displacement sensor
associated with hydraulic cylinders 28, a local or global
coordinate position or speed sensor associated with any linkage
member connecting work tool 16 to frame 42 or with work tool 16
itself, a displacement sensor associated with movement of operator
input device 48, or any other type of sensor known in the art that
may generate a signal indicative of a pivoting position or speed of
machine 10. This signal may be sent to controller 60 throughout
each excavation cycle. It is contemplated that controller 60 may
derive a pivot speed based on a position signal from first boom
sensor 62A and an elapsed period of time, if desired.
Second boom sensor 62B may be associated with the vertical pivoting
force of work tool 16 imparted by hydraulic cylinders 28 (i.e.,
associated with the lift force of boom member 24 relative to frame
42). Specifically, second boom sensor 62B may be a pressure sensor
associated with hydraulic cylinders 28 used to determine a force
thereof based on a measured pressure or pressure differential, a
strain gauge associated with the connection of boom member 24 to
frame 42, a type of load cell, or any other device known in the art
for monitoring a force and generating a signal in response thereto.
This signal may be sent to controller 60 throughout each excavation
cycle.
Swing sensor 64 may be associated with the generally horizontal
swinging motion of work tool 16 imparted by swing motor 49 (i.e.,
the motion of frame 42 relative to undercarriage member 44).
Specifically, swing sensor 64 may be a rotational position or speed
sensor associated with the operation of swing motor 49, an angular
position or speed sensor associated with the pivot connection
between frame 42 and undercarriage member 44, a local or global
coordinate position or speed sensor associated with any linkage
member connecting work tool 16 to undercarriage member 44 or with
work tool 16 itself, a displacement sensor associated with movement
of operator input device 48, or any other type of sensor known in
the art that may generate a signal indicative of a swing position
or speed of machine 10. This signal may be sent to and recorded by
controller 60 throughout each excavation cycle. It is contemplated
that controller 60 may alternatively derive a swing speed based on
a position signal from swing sensor 64 and an elapsed period of
time, if desired.
Bucket sensor 65 may be associated with the pivoting force of work
tool 16 imparted by hydraulic cylinder 38. Specifically, bucket
sensor 65 may be a pressure sensor associated with one or more
chambers within hydraulic cylinder 38, a strain gauge associated
with the pivot connection between work tool 16 and stick member 3,
a load cell, or any other type of sensor known in the art that
generates a signal indicative of a pivoting force of machine 10
during a dig and a dump operation of work tool 16. This signal may
be sent to controller 60 throughout each excavation cycle.
Stick sensor 67 may be associated with the vertical pivoting force
of work tool 16 imparted by hydraulic cylinder 36 (i.e., associated
with the lift force of stick member 30 relative to boom member 24).
Specifically, second stick sensor 67 may be a pressure sensor
associated with hydraulic cylinder 36 used to determine a force
thereof based on a measured pressure or pressure differential, a
strain gauge associated with the connection of stick member 30 to
boom member 24, a type of load cell, or any other device known in
the art for monitoring a force and generating a signal in response
thereto. This signal may be sent to controller 60 throughout each
excavation cycle.
Power source sensor 69 may be associated with power source 13 to
monitor a performance thereof. In one embodiment, power source
sensor 69 may embody a fuel consumption sensor configured to
generate a signal indicative of an amount of fuel being consumed by
power source 13. In another embodiment, power source sensor 69 may
embody a speed sensor, a temperature sensor, a torque sensor, or
any other sensor known in the art. It is contemplated that multiple
power source sensors 69 may be included within machine 10, if
desired. The signal(s) from power source sensor 69 may be directed
to controller 60 throughout operation of machine 10.
With reference to FIG. 3, a curve 68 may represent the swinging
speed of machine 10 throughout each segment of the excavation work
cycle, as recorded by controller 60 based on signals received from
sensor 64. During most of the dig segment, the swing speed may
typically be about zero (i.e., machine 10 may generally not swing
during a digging operation). At completion of a dig stroke, machine
10 may generally be controlled to swing work tool 16 toward the
waiting haul vehicle 12 (referring to FIG. 1). As such, the swing
speed of machine 10 may begin to increase toward the end of the dig
segment. As the swing-to-truck segment of the excavation work cycle
progresses, the swing speed may reach a maximum when work tool 16
is about midway between dig location 18 and dump location 20, and
then slow toward the end of the swing-to-truck segment. During most
of the dump segment, the swing speed may typically be about zero
(i.e., machine 10 may generally not swing during a dumping
operation). When dumping is complete, machine 10 may generally be
controlled to swing work tool 16 back toward dig location 18
(referring to FIG. 1). As such, the swing speed of machine 10 may
begin to increase toward the end of the dump segment. As the
swing-to-trench segment of the excavation cycle progresses, the
swing speed may reach a maximum in a direction opposite to the
swing direction of the swing-to-truck segment. This maximum speed
may generally be achieved when work tool 16 is about midway between
dump location 20 and dig location 18. The swing speed of work tool
16 may then slow toward the end of the swing-to-trench segment, as
work tool 16 nears dig location 18.
Controller 60 may partition a current excavation work cycle into
the four segments described above based on signals received from
sensors 62A, 64, and 65, and with reference to the swing speeds and
pivot forces of machine 10 recorded for a previous excavation work
cycle (i.e., with reference to curve 68 within map 66). Typically,
controller 60 may partition the excavation work cycle based on at
least three different conditions being satisfied, one condition
associated with the swing motion measured by sensor 62A, one
condition associated with the pivoting motion measured by sensor
64, and one condition associated with the pivot force measured by
sensor 65. For example, controller 60 may partition the current
excavation work cycle between the dig segment and the
swing-to-truck segment when a current swing speed of machine 10
exceeds an amount of the maximum swing speed recorded during the
previous swing-to-truck segment, when the pivot speed exceeds a
threshold speed value, and when the pivot force is less than a
threshold value. In one example, the amount may be about 20% of the
maximum swing speed recorded during the previous swing-to-truck
segment, while the threshold speed value may be about
5.degree./sec. The threshold pivot force may vary based on a size
of machine 10 and an application thereof. It is also contemplated
that the threshold pivot force, similar to the swing speed, may be
based on the maximum force generated during a previously recorded
cycle, if desired.
The excavation work cycle may be partitioned between the
swing-to-truck segment and the dump segment in a manner similar to
that described above. In particular, controller 60 may partition
the current excavation work cycle between the swing-to-truck
segment and the dump segment when a current swing speed of machine
10 slows to less than about 20% of the maximum swing speed recorded
during the previous swing-to-truck segment, when the pivot speed
slows to less than about 5.degree./sec, and when the pivot force
exceeds a threshold value.
In contrast to the dig and swing-to-truck segments, the dump
segment may be considered complete based on a current swing speed,
a current pivot direction, and a pivot force, regardless of pivot
speed. That is, controller 60 may partition the excavation work
cycle between the dump segment and the swing-to-trench segment when
a current swing speed of machine 10 exceeds about 20% of the
maximum swing speed recorded during the previous swing-to-trench
segment, when the pivot direction is toward dig location 18 (i.e.,
in a direction opposite from the pivot direction of the
swing-to-truck segment or in the same direction as the pull of
gravity), and when the pivot force is less than a threshold value.
It should be noted that, although shown as a negative speed by
curve 68, this negative aspect of the swing speed is simply
intended to indicate a direction of the swing speed in opposition
to the swing direction encountered during the swing-to-truck
segment. In some situations, the maximum swing speeds of the
swing-to-truck and swing-to-trench segments may have substantially
the same magnitude.
Controller 60 may partition the swing-to-trench segment from the
dig segment when a current swing speed of machine 10 slows to less
than about 20% of the maximum swing speed recorded during the
previous swing-to-trench segment, when the pivot speed is less than
about 5.degree./sec, and when the pivot force is greater than a
threshold amount. After this partition has been made, controller 60
may repeat the process with the next excavation work cycle that has
already been recorded.
In some situations, it may be beneficial to index each excavation
work cycle and/or each segment of each excavation work cycle
according to an elapsed period of time or a particular time of the
occurrence. In these situations, data acquisition system 50 may
include a timer 70 (referring to FIG. 2) in communication with
controller 60. Controller 60 may be configured to receive signals
from timer 70, and record performance information associated
therewith. For example, controller 60 may be configured to record a
total number of cycles completed within a user defined period of
time, a time required to complete each cycle, a number of segments
completed during the user defined period of time, a time to
complete each segment, an occurrence time of each cycle, an
occurrence time of each segment of each cycle, etc. Each work cycle
may be considered completed after the occurrence and detection of
each dump segment. This information may be utilized to determine a
productivity and/or efficiency of machine 10.
Controller 60 may also be configured to dynamically determine a
payload of work tool 16 based on signals from second boom sensor
62B, swing sensor 64, and stick sensor 67, and based on the
partitioned work cycle. In particular, after partitioning the work
cycle into the four segments described above, controller 60 may
select the swing-to-truck segment (i.e., the loaded swing segment)
for payload determination. By selecting the swing-to-truck segment
for payload determination, controller 60 may help ensure that all
of the material that will be loaded into work tool 16 has already
been loaded (i.e., that the dig segment is complete), and that no
material has been intentionally lost (i.e., that the dump segment
has not yet been completed) prior to the determination. Controller
60 may then determine a sampling period within the swing-to-truck
segment that may provide the most accurate payload
determination.
The sampling period may be a period of time within the
swing-to-truck segment when the velocities of work tool 16 are
substantially constant (e.g., when the swing velocity changes the
least). As can be seen from curve 68, the swing velocity may peak
at a point about halfway through the swing-to-truck segment, and
the sampling period may be generally positioned about this point of
maximum velocity. The sampling period may generally start and end
at about the same velocities (i.e., the bounds of the sampling
period may be associated with about the same velocity), and have a
duration that varies based on the peak swing speed and a quality of
payload samples taken during the sampling period. In one
embodiment, the velocities at the start and end of the sampling
period may be about 15 degrees/sec, and the number of quality
payload samples required to accurately determine the payload of
work tool 16 may be about 100.
Controller 60 may qualify each payload sample based on a predefined
criteria. That is, although controller 60 may continuously sample
the force signals from sensors 62B and 67 and the velocity signals
from sensors 62A and 64, through post-processing after completion
of the work cycle, controller 60 may only use those samples that
meet the predefined criteria. In this manner, accuracy of the
payload determination may be ensured. Thus, the sampling period may
vary in duration, and the start and end velocities bounding the
sampling period may change based on the total number of samples
within the period required to produce 100 qualified samples. The
predefined criteria may be associated with a number of directional
changes of work tool 16 requested by an operator of machine 10, a
velocity stability of boom member 24 and stick member 30, an
extension status of hydraulic cylinders 28 and 36, and an amount of
material spillage from work tool 16 during the sampling period. In
one example, no directional changes may be requested or implemented
during a qualified sample. In another example, the velocity of boom
member 24 and stick member 30 must remain constant within a
threshold amount during the qualified sample. In yet another
example, hydraulic cylinders 28 and 36 may not be at an end stop
during the qualified sample, or transitioning from a static
friction condition. In a further example, the material spillage
from work tool 16 must be less than a threshold amount during the
qualified sample. The threshold amounts may vary and be based on a
particular machine or application. Each sample taken by controller
60 that meets these criteria may be considered a qualified sample,
and be used for payload determination.
Controller 60 may utilized the qualified samples to determine
payload by reference to one or more maps stored within the memory
of controller 60. Specifically, these maps may relate signals from
sensors 62A, 62B, 64, and 67 that have passed the quality criteria
outlined above to a payload of work tool 16. Each of these maps may
include a collection of data in the form of tables, graphs, and/or
equations. In one example, a force related value calculated as an
function of the signals received from one or both of sensors 62B
and 67, and a speed related value calculated as a function of
signals from one or both of sensors 62A and 64 may be related to a
payload value in the maps. In one embodiment, the function utilized
to calculate the force related value may be an averaging function
that takes into account the 100 qualified samples obtained during
the sampling period. Similarly, the function utilized to calculate
the velocity related value may be an averaging function that takes
into account the 100 qualified samples obtained during the sampling
period.
It is contemplated that, as machine 10 ages, is serviced or
repaired, or components thereof are replaced, controller 60 may
require calibration to help ensure accuracy in payload
determination. In one embodiment, calibration can be performed
in-situ during a normal work cycle. That is, calibration may be
performed during the swing-to-trench segment of the work cycle when
work tool 16 is substantially empty. The calibration may be
performed by determining a payload during the empty swing segment,
and comparing the determined payload to the known weight of work
tool 16 stored in memory of controller 60. Alternatively or
additionally, a known weight may be loaded into work tool 16 during
the calibration process and used for comparison, if desired.
As illustrated in FIG. 4, controller 60 may link machine
performance, payload information, and power source performance to
cycle segmentation information during post-processing. That is,
during the operation of machine 10 and completion of the excavation
work cycle, controller 60 may continuously record the signals from
sensors 62A, 62B, 64, 65, 67, and 69. Based on the signals from
sensors 62A, 64, and 65, controller 60 may segment the work cycle
into four distinct segments. Based on signals from timer 30 and the
segmentation, controller 60 may determine machine performance
information associated with each of the segments (cycle time,
segment time, etc.). Based on the signals from sensors 62B, 64, and
67, controller 60 may determine a payload of work tool 16. And,
based on signals from sensor 69, controller 60 may determine a
performance (e.g., fuel consumption) of power source 13. Controller
60 may link all of this information together, and index the
information according to which segment of the work cycle was in
process at the time the data used to generate the information was
recorded.
For example, after completion of a first excavation work cycle,
controller 60 may partition the cycle into a first dig segment, a
first swing-to-truck segment, a first dump segment, and a first
swing-to-trench segment. Controller 60 may also determine a time
elapsed during completion of each of these segments and during
completion of the entire excavation work cycle. In addition,
controller 60 may determine a payload of work tool 16 and an amount
of fuel consumed by power source 13 during each segment and during
the entire cycle. Controller 60 may then link each segment to its
respective completion time, payload, and consumed fuel amount.
Controller 60 may analyze the linked information according to
operator request. Specifically, controller may utilize the timing,
payload, and fuel consumption information for a particular segment
or work cycle to determine a related performance parameter such as
an amount of material moved per unit of fuel consumed (e.g.,
tones/liter); an amount of material moved per unit of time, per
segment, or per cycle (e.g., tones/hr, tones/swing segment,
tones/cycle, etc.); an efficiency of machine 10; and/or an idle
time (i.e., wait time) of machine 10. The idle time may be
considered the time during which the signals from sensors 62A, 62B,
64, 65, 67, and/or 69 indicate little movement of machine 10 or
movement that can not be properly classified into one of the four
segments. The operator may request specific performance parameters
via an onboard interface device (e.g., computer console) that is
hard wired to controller 60, via a portable device such as a laptop
computer or PDA that is selectively connected to controller 60,
and/or via a remote system that is wirelessly connected to
controller 60. The different performance parameters may be selected
from a list of available parameters and/or defined by the
operator.
Controller 60 may also be configured to alert an operator of
machine 10 when the linked performance parameters for at least one
of the plurality of segments deviate from a threshold performance
level. That is, the operator may establish the threshold
performance level expected from machine 10 during each work cycle
and/or during each segment of each work cycle. During post
processing, controller 60 may compare the actual performance
parameters to the threshold performance parameters and, based on
the comparison, alert the operator when the actual performance of
machine 10 is less than expected. It is contemplated that the
threshold performance levels may, alternatively, be automatically
generated based on the average performance parameters recorded
during previous work cycles (e.g., based the average performance
parameters from a particular segment of multiple previously
executed work cycles).
INDUSTRIAL APPLICABILITY
The disclosed data acquisition system may be applicable to any
excavation machine that performs a substantially repetitive work
cycle, where knowledge about the performance of the machine during
particular segments of the excavation work cycle is important. The
disclosed data acquisition system may link the performance
parameters to particular segments of the work cycle during which
the associated information was recorded. The disclosed data
acquisition system may also analyze the information according to
operator request and established performance thresholds.
Several benefits may be associated with the disclosed data
acquisition system. For example, by indexing the performance
parameters according to work cycle segmentation, an operator or
analyst might be able to retrieve information specific to a
particular segment, a particular type of segment, a particular work
shift, a particular work cycle, etc. In addition, the operator or
analyst may be able to easily compare the performance of machine 10
during one segment, one type of segment, one work cycle, one work
shift, etc. to another.
It will be apparent to those skilled in the art that various
modifications and variations can be made to the disclosed data
acquisition system. Other embodiments will be apparent to those
skilled in the art from consideration of the specification and
practice of the disclosed data acquisition system. It is intended
that the specification and examples be considered as exemplary
only, with a true scope being indicated by the following claims and
their equivalents.
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